Question

Решите систему уравнений:
$left { {{x^{2+10xy+25y^{2} =9} } atop {x-5y=7}} right.$

Answer 1

$left { {{x^{2}+10xy+25y^{2}=9} atop {x-5y=7}} right.\\left { {{(x+5y)^{2}=9 } atop {x-5y=7}} right.\\1)+left { {{x+5y=-3} atop {x-5y=7}} right.\ --------\2x=4\\x_{1} =2\\2-5y=7\\5y=-5\\y_{1}=-1 \\2)+left { {{x+5y=3} atop {x-5y=7}} right.\-------\2x=10\\x_{2}=5\\5-5y=7\\5y=-2\\y_{2}=-0,4$

Ответ : (2 ; - 1) , (5 ; - 0,4)